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Summer Driving

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SaxMan

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I had Baby Blue out each day of the weekend, going hither and yon with it, and the car ran very well for the most part. My daughter and I went out for a long ride today, to the point where she didn't even complain when I finally pointed the car home (she usually protests most vociferously when she realizes we're going home). It looks like I've stopped those pesky antifreeze leaks (fingers crossed). Today (Monday) the temperatures reached into the upper 80s. The two things I noticed was that my idle speeds are lower on hot days and that my temperature gauge starting hanging out around the "N" for the first time. At stoplights, it began heading towards the "H", but never made it into the warning area.

With the carbs, I figure I'd just do an idle adjustment to raise the rpms a smidge. Should I also be looking at a mixture adjustment? I'm curious as to the "science" behind this: Warmer tempertures = less dense air = leaner mixture & lower rpms?...is that correct? Right now, I'm happy with the carbs, so I'm a bit reticent to start playing with them unless I have to.

For regulating the temperature -- should I keep my foot on the gas at lights so the fan can turn quicker? It didn't seem to make much difference. The biggest thing about getting the temps
 
On hot days when the car was totally warmed up and the idle dropped til the car almost stalled out, I used to pull out the choke a smidge. If your choke is properly adjusted, the first 1/4 inch of pull on the knob only adds fuel, not choke at all. ..

I've since gone to a Weber DGV and no longer have to deal with that.
 
I guess our minds think alike...when the idle dropped the point where the car was flirting with stalling, I did pull the choke out to bring up the rpms. It was idling on its own around 700 rpm, although it was shaking a good deal. I know "the book" says they should idle at 800, but I try to keep mine between 900 to 1000 rpm at idle to keep the generator happy.
 
The condition you are talking about could be a vacuum leak when it gets hot. Idle speed should not vary that much due to coolant temperatures. Check your manifold nuts.
Scott in CA
 
It's more a heat under the hood issue than coolant temp issue.
 
Keep an eye on the fan belt.

Don't run TOO MUCH anti-freeze in the mix (anti-freeze doesn't reject heat as well as water......in your area, 1/3 anti-freeze and 2/3 water is plenty in the summer).

Be sure the lower hose isn't too soft. That hose in under suction. If it gets old, it will collapse and restrict coolant flow.

900 to 1000 RPM idle is no big deal.
 
Fan belt and hoses are all brand new, so we're probably good to go. I run the premixed 50/50 coolant -- maybe I should dilute it additionally?
 
I had the same problem with Ms Triss for years. It would get hot and the idle would drop and she would stall or come close and I would have to feather the throttle or pull out the choke a bit exactly as described. After thinking about this for about five years, I finally came up with a solution. I adjusted the idle to 800 rpm - when the car was hot!!! Doh.

idles perfectly now. (Too soon old to late smart)
 
JPSmit said:
I had the same problem with Ms Triss for years. It would get hot and the idle would drop and she would stall or come close and I would have to feather the throttle or pull out the choke a bit exactly as described. After thinking about this for about five years, I finally came up with a solution. I adjusted the idle to 800 rpm - when the car was hot!!! Doh.

idles perfectly now. (Too soon old to late smart)
Click to expand...

Now there is thinking for ya! I'll have to try that. I just parked Spritey a few minutes ago after a quick drive and I was doing my perennial thinking on that matter. I too always pull out my throttle slightly; however, it is an aftermarket item installed by the PO and it does not stay out. On my BJ8, the throttle/choke knob turns so you can lock it into position. Did the original Spridget cable have this feature?
 
The Mark IV's choke can be locked in position...mine's a bit worn out, so locking is a 50/50 proposition. What I did was cut a piece of excess hose when I replaced the oil breather hose, split it and use it as a shim to hold the choke open. When the car is warm, I pull it off and put it back in the center console.

I know I'll have to replace the choke cable one day, but I really don't feel like dismantling the dashboard to do it....at least not until next winter.
 
Others have used clothes pegs to hold open the choke
 
Yes, the choke knob should be able to be locked into postiion by a 1/4 twist. .. An old trick, as I hear tell, was to carry a clothes pin and stick that between the knob and the dash.
 
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